This is the stock World Fomula Intake Manifold for the Stock World Formula PZ 26 Walbro Carb
(Briggs Part # 557009)
It can also be used to mount a 28mm Mikuni by using a straight piece of rubber hose and 2 hose clamps.
OPTIONAL ADD-ON ACCESSORIES:
You may also want the Rubber Carb Spacer to mount the stock PZ 26 Walbro carb $11.95